Various compositions and devices meant to release a fragrance over a long period of time are well known. The fragrances employed include both aromatic and perfumed compositions. An early form of such a device, and one still in use, was a pomander made by studding an apple or orange with cloves, used as a garment sachet. Another approach still in use is to enclose dried leaves or flower petals in a perforated bag, box, or other container. More recently, various solid substrates such as waxes or polymeric materials have been impregnated with fragrances and used, for example, as room air-fresheners. In such applications, a steady and controlled rate of release of the fragrance from the substrate is a desirable attribute. The use of waxes or polymeric materials as substrates or carriers has the further advantage that the fragrance-containing material can readily be formed or cut into virtually any desired shape or size.
As specific examples of prior art materials, U.S. Pat. No. 2,169,055 discloses sheets of plasticized cellulose acetate containing essential oils; U.S. Pat. No. 3,655,129 discloses a polymeric substrate in which is dispersed droplets of a liquid non-solvent containing fragrance oil; and U.S. Pat. No. 4,051,159 discloses a transparent article comprising a mixture of a polyamide resin, a long-chain alkyl alcohol, and a fragrance material. A somewhat different, but related, approach is that disclosed in U.S. Pat. No. 3,544,364 naming Rudner et al as inventors. In this case a solid hydroxylated substrate such as paper or cotton is treated with a prolonged odor releasing composition.
Each of the prior art compositions has some disadvantage such as high cost, inadequate rate of release of the fragrance, difficulty in forming and maintaining a desired shape, and so on. These disadvantages have led to a continuing search for improvements in odor-releasing compositions.
We have found that the disadvantages or prior compositions can be overcome, and that improvements can be obtained, by the use of certain polyurethane foam compositions as carriers for fragrances, in the manner described herein.